package oop;

import java.util.ArrayList;

public class Unit50 {
	public static void main(String[] args){
		ArrayList<A1> al = new ArrayList<A1>();
		al.add(new A1());
		
		ArrayList<C1> al1 = new ArrayList<C1>();
		al1.add(new C1());
		al1.add(new D1());
		
	}
}

class A1{
	public void show(){
		
	}
}

class B1{
	public void go(){
		
	}
}


class C1{
	
}

class D1 extends C1{
	
}